*{
    padding: 0;
    margin: 0;
}
.Main-nav{                  /* 侧边导航栏*/
    left: 0;
    top: 0;
    width: 150px;
    height: 100%;
    background: rgb(51, 55, 68);
    position: fixed;
    text-align: center;
}
.Main-nav li{
    color: whitesmoke;
    display: inline-block;
    width: 100%;
    height: 50px;
    line-height: 50px;
    text-decoration: none;
    margin: 10px 0;
    font-size: 20px;
    cursor: pointer;
    user-select: none;
}
.Main-nav li:hover{
    background: rgb(30, 33, 41);
}


